The present invention is generally directed to improvements in the color video processing art. More particularly, the present invention is directed toward providing circuitry for a widebans RGB video processor. Even more particularly, the present invention is directed toward providing circuitry for a wide band analog RGB video processor having capability for negative feedback black level control.
In television and other color video monitor applications, a color video signal typically comprises red (R), green (G), and blue (B) components. A received signal typically may be separated into R, G and B components, amplified and then applied to appropriate R, G and B inputs of a cathode ray tube (CRT) color display terminal for visual display. Also, gain, contrast and sometimes black level controls commonly may be provided for customer adjustment of the displayed video signal.
Various applications, including those in which computers contain drive circuits that interface with CRT display devices, create the desirability for the amplifying, or RGB video processing, stage to operate efficiently and accurately through a wide band of video frequencies which may be encountered. Accordingly, it may be desirable to provide a wideband RGB video processor for use in color televisions and color video monitors.
However, efforts to provide a wide band RGB processor may frequently be frustrated by an undesired limiting effect on the signal slew rate caused by the relatively large voltage swings in a typical video signal.
Further, it may be desirable to provide feedback control circuitry for video monitors for stabilizing the black level of the video display and overcoming other signal distortions which may be incurred during RGB processing. The desired stabilizing would take into account such variations as may be induced by the gains control circuit, or temperature fluctucations, and other extraneous variations which may be induced by component value fluctuations. Optimally accurate feedback information would then be desired so as to compensate as nearly as possible for all distortions which may occur during the RGB processing.
Thus, a principal object of the present invention is to generally overcome deficiencies which exist in the prior art and to provide an improved RGB video processor.
It is a further object of the present invention to provide a wideabnd RGB video processor and RGB video processing method for color television and color video monitor applications without limiting the slew rate.
It is a still a further object of the present invention to provide feedback control capability for a video monitor for stabilizing the video display signal at the video output stage.